Magnetism

Versarien launches graphene-based superparamagnetic material

Versarien has announced the launch of a new hybrid nanomaterial that has superparamagnetic properties, which can be used across a range of applications, like defense and healthcare. The new material combines graphene with both iron oxide and manganese oxide nanoparticles and its development was led by Versarien's 62% owned subsidiary, Gnanomat.

The superparamagnetic material combines graphene with both iron oxide and manganese oxide nanoparticles that provide the material with magnetic properties. In return, graphene provides electrical conductivity to these electrically insulating metal oxides. Magnetic nanocomposites can readily respond to external magnetic fields which allow them to be manipulated. Potential applications of the material include the treatment of wastewater whereby pollutants are adsorbed onto the graphene surface. The material could also lends be used in biomedical and biotechnology applications, or defense applications requiring the shielding of electromagnetic fields. Magnetic manipulation could allow the recovery and recycling of the graphene, something that could not be done with normal graphene compounds.

Read the full story Posted: Jun 27,2022

Graphene enables scientists to gain new clarity in visualizing the quantum realm

Scientists from Princeton, the University of Leeds, the University of California and the National Institute for Material Science in Japan have used innovative techniques to visualize electrons in graphene, and found that strong interactions between electrons in high magnetic fields drive them to form unusual crystal-like structures similar to those first recognized for benzene molecules in the 1860s by chemist August Kekulé.

Scientists visualize electron crystals in a quantum superposition image

These crystals exhibit a spatial periodicity that corresponds to electrons being in a quantum superposition. The experiments also showed the Kekulé quantum crystals have defects that have no analog to those of ordinary crystals made up of atoms. These findings shed light on the complex quantum phases electrons can form because of their interaction, which underlies a wide range of phenomena in many materials.

Read the full story Posted: Feb 24,2022

Researchers detect abnormally strong absorption of light in magnetized graphene

Researchers from Germany's University of Regensburg, Russia's MIPT, and U.S-based University of Kansas and MIT have discovered an abnormally strong absorption of light in magnetized graphene. The effect appears upon the conversion of normal electromagnetic waves into ultra-slow surface waves running along graphene. The phenomenon could help develop new ultra-compact signal receivers with high absorption efficiency for future telecommunications.

Magnetized graphene displays abnormal light absorption image

Everyday experience teaches us that the efficiency of light energy harvesting is proportional to the absorber area, as indicated by solar panel "farms" covering large areas. But can an object absorb radiation from an area larger than itself? It appears that way, and it is possible when the frequency of light is in resonance with the movement of electrons in the absorber. In this case, the area of radiation absorption is on the order of the light wavelength squared, although the absorber itself can be extremely small.

Read the full story Posted: Feb 20,2022

Researchers stabilize the edges of graphene nanoribbons and measure their magnetic properties

Researchers at Lawrence Berkeley National Laboratory (Berkeley Lab) and UC Berkeley have developed a method to stabilize the edges of graphene nanoribbons and directly measure their unique magnetic properties.

The team, co-led by Felix Fischer and Steven Louie from Berkeley Lab’s Materials Sciences Division, found that by substituting some of the carbon atoms along the ribbon’s zigzag edges with nitrogen atoms, they could discretely tune the local electronic structure without disrupting the magnetic properties. This subtle structural change further enabled the development of a scanning probe microscopy technique for measuring the material’s local magnetism at the atomic scale.

Read the full story Posted: Dec 27,2021

Researchers take a step towards achieving topological qubits in graphene

Researchers from Spain, Finland and France have demonstrated that magnetism and superconductivity can coexist in graphene, opening a path towards graphene-based topological qubits.

Schematic illustration of the interplay of magnetism and superconductivity in a graphene grain boundary imageSchematic illustration of the interplay of magnetism and superconductivity in a graphene grain boundary, a potential building block for carbon-based topological qubits Credit: Jose Lado/Aalto University

In the quantum realm, electrons can behave in interesting ways. Magnetism is one of these behaviors that can be seen in everyday life, as is the rarer phenomena of superconductivity. Intriguingly, these two behaviors are often antagonists - the existence of one of them often destroys the other. However, if these two opposite quantum states are forced to coexist artificially, an elusive state called a topological superconductor appears, which is useful for researchers trying to make topological qubits.

Read the full story Posted: Apr 29,2021

Researchers manage to induce “artificial magnetic texture” in graphene

An international research team, led by the University at Buffalo, has reported an advancement that could help give graphene magnetic properties. The researchers describe in their work how they paired a magnet with graphene, and induced what they describe as artificial magnetic texture in the nonmagnetic material.

Induced magnetism in graphene could also promote spintronics imageThe image shows eight electrodes around a 20-nanometer-thick magnet (white rectangle) and graphene (white dotted line). Credit: University at Buffalo.

Independent of each other, graphene and spintronics each possess incredible potential to fundamentally change many aspects of business and society. But if you can blend the two together, the synergistic effects are likely to be something this world hasn’t yet seen, says lead author Nargess Arabchigavkani, who performed the research as a PhD candidate at UB and is now a postdoctoral research associate at SUNY Polytechnic Institute.

Read the full story Posted: Feb 27,2021

Graphene/hBN SQUID detects even the faintest magnetic fields

Researchers at the University of Basel in Switzerland, Budapest University of Technology and Economics in Hungary and National Institute for Material Science in Japan have developed a new, super-small device that is capable of detecting minute magnetic fields.

Conventional vs. new SQUID imageA conventional SQUID (left) and the new SQUID (right). (University of Basel, Department of Physics)

The device, a new kind of superconducting quantum interference device (SQUID), is just 10 nanometres high, or around a thousandth of the thickness of a human hair. It's made from two layers of graphene making it one of the smallest SQUIDs ever built separated by a very thin layer of boron nitride.

Read the full story Posted: Sep 14,2020

Graphene acts as superconductor, insulator and ferromagnet in a single device

A collaborative group of scientists has designed a device that makes use of graphene’s assorted talents: superconducting, insulating, and a type of magnetism called ferromagnetism. The multitasking device could enable new physics experiments, such as research in the pursuit of an electric circuit for faster, next-generation electronics like quantum computing technologies.

The graphene deviceon a silicon dioxide/silicon chip imageAn optical image of the graphene device (shown above as a square gold pad) on a silicon dioxide/silicon chip. Shining metal wires are connected to gold electrodes for electrical measurement. (Credit: Guorui Chen/Berkeley Lab)

So far, materials simultaneously showing superconducting, insulating, and magnetic properties have been very rare. And most people believed that it would be difficult to induce magnetism in graphene, because it’s typically not magnetic. Our graphene system is the first to combine all three properties in a single sample, said Guorui Chen, a postdoctoral researcher in Wang’s Ultrafast Nano-Optics Group at UC Berkeley, and the study’s lead author.

Read the full story Posted: Mar 05,2020

Stanford team finds novel form of magnetism in twisted bi-layer graphene

Stanford physicists recently observed a novel form of magnetism, predicted but never seen before, that is generated when two graphene sheets are carefully stacked and rotated to a special angle. The researchers suggest the magnetism, called orbital ferromagnetism, could prove useful for certain applications, such as quantum computing.

bi-layer graphene between hBN gives off orbital ferromagnetism imageOptical micrograph of the assembled stacked structure, which consists of two graphene sheets sandwiched between two protective layers made of hexagonal boron nitride. (Image: Aaron Sharpe)

We were not aiming for magnetism. We found what may be the most exciting thing in my career to date through partially targeted and partially accidental exploration, said study leader David Goldhaber-Gordon, a professor of physics at Stanford’s School of Humanities and Sciences. Our discovery shows that the most interesting things turn out to be surprises sometimes.

Read the full story Posted: Jul 28,2019

Graphene enables researchers to control infrared and terahertz waves

Researchers from the University of Geneva (UNIGE) in Switzerland and the University of Manchester in the UK have found an efficient way to control infrared and terahertz waves using graphene. "There exist a class of the so-called Dirac materials, where the electrons behave as if they do not have a mass, similar to light particles, the photons," explains Alexey Kuzmenko, a researcher at the Department of Quantum Matter Physics in UNIGE's Science Faculty, who co-conducted this research together with Ievgeniia Nedoliuk.

The interaction between graphene and light suggests that this material could be used to control infrared and terahertz waves. "That would be a huge step forward for optoelectronics, security, telecommunications and medical diagnostics," points out the Switzerland-based researcher.

Read the full story Posted: Jul 22,2019